Electromagnetic conveying trough

ABSTRACT

An electromagnetic conveying trough of the type having an upwardly sloping trough body in which the liquid metal that is to be conveyed is driven upwards by a traveling electromagnetic field generated by an inductor and a gate in the body of the trough for limiting the layer thickness of the liquid metal, the mean direction of the gate opening in a direction perpendicular to the effective component of the traveling electromagnetic field not exceeding 80 percent, and preferably not 75 percent, of the mean width of that portion of the trough that precedes the gate in the direction of axial flow.

United States Patent Von Starck et al.

[ 3,738,778 June 12, 1973 1,203,916 3/1970 Great Britain TROUGHInventors: Axel Von Starck,

Remscheid-Luttringhausen' Hans Primar t t y Exammer-Wdham L. Freeh ErwmGerblg Remscheld both of Assistant Examiner-John F. Winburn GermanyAttorney-Cushman, Darby & Cushman [73] Assignee: AEG-Elotherm GmbH,

Remscheid-Hasten, Germany Aug. 10, 1971 [57] ABSTRACT I Anelectromagnetic conveying trough of the type having an upwardly slopingtrough body in which the liquid metal that is to be conveyed is drivenupwards by a '22 Filed:

traveling electromagnetic field generated by an induc-' tor and a gatein the body of the trough for limiting the layer thickness of the liquidmetal, the mean direction of the gate opening in a directionperpendicular to the effective component of the travelingelectromagnetic field not exceeding percent, and preferably not 75percent, of the mean width of that portion of the trough that precedesthe gate in the direction of axial flow.

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D n 4 M .m m m .m m mm" 5 m m mmm M .K W "U" m w 1 A .1 NWT u H m 0 l w"ms N W q I." 0 m CH M. F .M P m mfw A DJ UIF u m mum 2 3 555 rt [[21 7Claims, 4 Drawing Figures [56] References Cited UNITED STATES PATENTS3,486,660 12/1969 222/76 3,534,886 10/1970VonStarck..........L...............417/50 5712514 it i ELECTROMAGNETICCONVEYING TROUGH This invention relates to an electromagnetic conveyingtrough comprising an upwardly sloping trough body in which the liquidmetal that is to be conveyed is driven upwards in open flow against theforce of gravity by the traveling electromagnetic field of a polyphasetraveling field inductor, and a gate in the body of the trough forlimiting the layer thickness of the flowing metal.

A conveying trough of this kind is described in the publishedspecification of German Patent application No. 1,949,982. It is usedwith particular advantage in automated foundries where the sameaccurately metered volumes of metal are cast in quick succession. Theobject of the present invention is to further improve the accuracy ofthe rate of metal discharge from the upper end of such a trough.

According to the invention, this object is achieved in that the averagedimension of the cross section of the gate opening in a directionperpendicular to the effective component of the travelingelectromagnetic field does not exceed 80 percent, and is preferably notmore than 75 percent of the average width, measured in the samedirection, of that portion of the trough which precedes the gate in thedirection of metal flow. It is believed that this has the effect of moreprecisely defining the density of force acting on the liquid in the gateopening and of thereby more precisely controllingthe rate of flow.

Besides this advantage the invention also permits choosing a desiredconveying capacity that is easilyvariable within wide limits by the useof a conveying trough designed for a given maximum conveying capacity.It has been found that in electromagnetic conveying troughs the maximumconveying capacity, i.e. the maximum mechanical conveying power relatedto the effective power consumed by the traveling field inductor, can bereached only if the pitch of the poles of the traveling field inductoris about 3.5 to 6 times the thicknessof the refractory lining betweenthe bottom of the trough and the active inductor surface and if theinternal width of the trough is about 1.2 to 2 times the pitch of thepoles. Since the thickness of the refractory lining cannot bearbitrarily reduced for technological reasons, there is a minimum widthof the conveying trough at which, at least approximately, a maximumconveying efficiency can be achieved. Since the size of the gate openingcodetermines the rate of flow through the gate, the inventionfacilitates adapting an electrotion of its length not exceeding thepitch and preferably not exceeding half the pitch of the poles of thetraveling field inductor contracts to the size of the gate opening.Conveniently the side walls of the trough project to form shoulders atthe gate against which more particularly an adjustably movable slidinggate can bear for limiting the layer thickness of the flowing metal.

The invention will be hereinafter more particularly described withreference to the drawings which exemplify the invention.

FIG. 1 is the outlet end of an embodiment of the trough, in a sectiontaken on the line AA in FIG. 2, which shows the same embodiment in crosssection (on the line 8-8) in FIG. 1.

FIGS. 3 and 4 showin a representation analogous to FIGS. 1 and 2-adifferent embodiment of the proposed trough in which the gate opening isadjustable, the construction of the trough being otherwise unchanged.

This electromagnetic conveying trough structurally consists of a bottomcasing'portion as shown in FIG. 2 and an upper casing portion 2. Theupper end of this electromagnetic conveying trough terminates in a spout3, whereas the bottom end, in FIG. 1 further towards the left in thedrawing, merges, for instance, into a melting or holding furnace (notshown in the drawing).

The bottom casing portion 1 (FIG. 2) contains a traveling field inductorwound on a slotted laminated core 4, the windings 5 of the inductorbeing inserted into the slots. The bottom casing portion 1 and the upperportion 2 are interconnected by flanges 6 between which a plate ofnonmagnetic steel 7 is clamped to form the cover of the bottom casingportion 1. The refractory body of the trough proper consists of a lining8rarnmed into the upper casing portion 2. In the region of the two lastpoles at the upper end of the traveling field inductor, a gate 9 iscemented into this lining. The opening 10 of the gate 9 has arectangular crosssection of a thickness d and-in a directionperpendicular to the ef-.

fective component of the traveling electromagnetic field, i.e. in theillustrated case parallel to the floor of the trougha width b that doesnot exceed 80 percent and preferably not 75 percent of the average width0 of the trough section preceding the gate in the direction of flow.When the traveling field inductor is switched on, the liquid metal isdriven against the gate and magnetic conveying trough that has beendesigned to function with optimum conveying efficiency at a giveninternal width and width of inductor to operate at different desiredrates of flow.

In a preferred embodimentof the invention, particularly when using thetrough for pouring equal volumes of metal in serial succession, the gateis located in the region of the last two poles of the traveling fieldinductor at the upper end of the trough.

According to another important aspect of the invention, at least one ofthe dimensions of the usually substantially rectangular cross section ofthe opening of the gate is adjustable, and in a preferred modificaionthe internal width of the trough is approximately constant, as isconventional, along the major portion of its length preceding the gate,but immediately preceding the gate the internal width of the troughwithin a porslightly backs up against this obstacle. It has been foundthat the rate at which the metal flows through the opening is inpractice independent of the level of the metal bath in the melting orholding furnace.

Contrary to FIG. 2, the trough in FIG. 4 is shown including its cover 11which is connected to the upper casing portion 2 by flanges 12, andwhich contains a thermally insulating lining I3. The internal width ofthe trough which is at least approximately-constant along the majorportion of its length preceding the gate 14 in this embodiment contractswithin a length of not more than the pitch and preferably not more thanhalf the pitch of the poles by virtue of the wall portions 15 projectinginwards to the width b of the gate opening. The shoulders facing thetrough outlet of these projecting wall portions 15 bear against asliding gate 16 formed by a refractory brick which by its adjustableelevation determines the height of the opening. The sliding gate 16 ismounted in a holder 17 suspended by a screw 18 in an eye 19 in the cover1 1 of the trough and its height can be adjusted by rotation of a nutand counternut 21 and fixed in the adjusted position. This type of gateis preferably used when such a conveying trough is employed in a foundryfor pouring consecutive series of castings which differ considerably inweight from series to series.

Many changes and modifications in the above embodiments of the inventioncan of course be made without departing from the scope of the invention.Accordingly, that scope is intended to be limited only by the scope ofthe appended claims.

What is claimed is: i

1. In an electromagnetic conveying trough comprising an upwardly slopingtrough body in which the liquid metal that is to be conveyed is drivenupwards in open flow against the force of gravity by the travelingelectromagnetic field of a polyphase traveling field inductor, and agatein the body of the trough for limiting the layer thickness of theflowing metal, the improvement wherein a first mean dimension of widthof the cross section of the gate opening in a direction perpendicular tothe effective component of the traveling electromagnetic field andperpendicular to the direction of liquid metal flow does not exceed 80percent of the mean width measured in the same direction of that portionof the trough that precedes the gate in the direction of metal flow andwherein a second mean dimension of height of the cross section of thegate opening in a direction perpendicular to both said first meandimension and the direction of liquid metal flow is less than thethickness of said metal layer in that portion of the trough thatimmediately precedes the gate in the direction of metal flow.

2. In an electromagnetic conveying trough as in claim 1, the furtherimprovement wherein the gate is provided in the region of the two lastpoles of the traveling field inductor.

3. In an electromagnetic conveying trough as in claim 1, the furtherimprovement wherein at least the height dimension of the, at leastsubstantially, rectangular cross section of the gate is adjustable.

4. In an electromagnetic conveyor trough as in claim 1, the furtherimprovement wherein the internal width of the trough is at leastapproximately constant within the major portion of the length of thetrough preceding the gate, but immediately preceding the gate theinternal width of the trough within a portion of its length notexceeding the pitch of the traveling inductor contracts to the size ofthe gate.

5. In a conveyor trough as in claim 1, the further improvement whereinthe internal width of the trough within a portion of its length notexceeding half the pitch of the poles contracts to the gate size.

6. In an electromagnetic conveying trough as in claim 1, the furtherimprovement wherein the side walls of the trough project to formshoulders at the gate against which an adjustably movable sliding brickcan bear for limiting the layer thickness of the flowing metal.

7. In a trough as in claim 1, the further improvement wherein the crosssection of the gate opening in a direction perpendicular to theeffective component of the traveling electromagnetic field does notexceed percent of the mean width of the portion of the trough thatprecedes the gate.

1. In an electromagnetic conveying trough comprising an upwardly slopingtrough body in which the liquid metal that is to be conveyed is drivenupwards in open flow against the force of gravity by the travelingelectromagnetic field of a polyphase traveling field inductor, and agate in the body of the trough for limiting the layer thickness of theflowing metal, the improvement wherein a first mean dimension of widthof the cross section of the gate opening in a direction perpendicular tothe effective component of the traveling electromagnetic field andperpendicular to the direction of liquid metal flow does not exceed 80percent of the mean width measured in the same direction of that portionof the trough that precedes the gate in the direction of metal flow andwherein a second mean dimension of height of the cross section of thegate opening in a direction perpendicular to both said first meandimension and the direction of liquid metal flow is less than thethickness of said metal layer in that portion of the trough thatimmediately precedes the gate in the direction of metal flow.
 2. In anelectromagnetic conveying trough as in claim 1, the further improvementwherein the gate is provided in the region of the two last poles of thetraveling field inductor.
 3. In an electromagnetic conveying trough asin claim 1, the further improvement wherein at least the heightdimension of the, at least substantially, rectangular cross section ofthe gate is adjustable.
 4. In an electromagnetic conveyor trough as inclaim 1, the further improvement wherein the internal width of thetrough is at least approximately constant within the major portion ofthe length of the trough preceding the gate, but immediately precedingthe gate the internal width of the trough within a portion of its lengthnot exceeding the pitch of the traveling inductor contracts to the sizeof the gate.
 5. In a conveyor trough as in claim 1, the furtherimprovement wherein the internal width of the trough within a portion ofits length not exceeding half the pitch of the poles contracts to thegate size.
 6. In an electromagnetic conveying trough as in claim 1, thefurther improvement wherein the side walls of the trough project to formshoulders at the gate against which an adjustably movable sliding brickcan bear for limiting the layer thickness of the flowing metal.
 7. In atrough as in claim 1, the further improvement wherein the cross sectionof the gate opening in a direction perpendicular to the effectivecomponent of the traveling electromagnetic field does not exceed 75percent of the mean width of the portion of the trough that precedes thegate.